摘要:

Shape change and release reaction indicate different degrees of the complex platelet response termed activation. Aggregation is a variable consequence of activation. Aggregation shows a temperature dependency opposite to that shown by the preceding shape change. Aggregation increases at lower temperature and requires, in contrast to activation, extracellular Ca2+, stirring, and at a low degree of activation the presence of fibrinogen. Aggregation can enhance activation by triggering prostaglandin endoperoxide-thromboxane synthesis. If activation reaches a high level associated with the release reaction, activation is further amplified by prostaglandin endoperoxide-thromboxane synthesis emerging independent of aggregation. These mechanisms of amplification of activation are blocked by indomethacin, an inhibitor of prostaglandin endoperoxide-thromboxane synthesis = anti-activating agent. In contrast, anti-aggregating agents, exemplified here with n-acetyl neuraminic acid, attack the aggregation of activated platelets but neither activation nor prostaglandin endoperoxide-thromboxane synthesis. Its anti-aggregating effect, in addition, enables n-acetyl neuraminic acid to imitate the inhibitory effect of indomethacin on the feedback amplification which results from aggregation. Anti-aggregating agents as characterized here may open a new valuable concept for anti-aggregation in vivo.

ISSN:1424-8832    

DOI:10.1159/000214294

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Platelet function was evaluated in platelet-rich plasma and in washed platelets in relation to their lipid composition, in 18 type II B hyperlipoproteinemic men treated with procetofene. The results were compared to those obtained in 15 young, healthy normolipemic controls and in 22 untreated male subjects with type II B hyperlipoproteinemia. In addition to completely normalizing platelet functions, procetofene was able to induce a 28–53% decrease in serum cholesterol and triglycerides. Solely, the aggregation to ADP (secondary), arachidonic acid and epinephrine was higher in the untreated hyperlipoproteinemic subjects. This increased susceptibility to aggregation does not appear to be related to the cholesterol or cholesterol-phospholipid content of platelet

ISSN:1424-8832    

DOI:10.1159/000214295

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The case history is presented of a woman aged 38 who received warfarin treatment because of a mitral valve replacement. During the first trimester of pregnancy, her prothrombin time was 20% of normal and kept at 40% until the 38th week of gestation. Then the patient received heparin until a few days after delivery of a normal child.

ISSN:1424-8832    

DOI:10.1159/000214296

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Human blood platelets were labeled with 51Cr and whole blood was reconstituted. The endothelium of rabbit abdominal aorta was removed with a balloon catheter and the inverted aorta was placed on a Plexiglas rod in a perfusion chamber. The reconstituted blood was perfused through the chamber of 10 min. Radioactivity of the aorta was measured and found to be mainly caused by the labeled platelets. The platelet deposition on the damaged aorta was measured before and after ingestion of 0.5 g acetylsalicylic acid twice a day for 1 week, and was found to be reduced after the use of this drug.

ISSN:1424-8832    

DOI:10.1159/000214297

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The absorption of factor VIII from gel filtration fractions, concentrates and plasma by aluminium hydroxide has been studied. Significant quantities of factor VIII could be removed when the protein concentration was low; the percentage absorbed increased with decreasing initial protein concentration. Factor VIII R:Ag and VIII:C were removed in parallel, but absorption of a high purity concentrate resulted in selective absorption of the lower molecular weight forms of factor VIII. Elution of the absorbed proteins gave a poor yield of VIII R:Ag, with no detectable VIII:C. Absorption of plasma showed no detectable loss of VIII R:Ag, but an apparent decrease of VIII:C of about 10%.

ISSN:1424-8832    

DOI:10.1159/000214298

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Prostaglandins play an important role in the platelet-vessel wall interactions. Superfusion with PGI2 of arterial segments prepared in an in vivo model for thrombus induction resulted in a very marked dose-effect-related decrease of white arterial thrombus formation.

ISSN:1424-8832    

DOI:10.1159/000214299

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:1424-8832    

DOI:10.1159/000214300

出版商:S. Karger AG    

年代:1979

数据来源: Karger